The present invention relates to the utilization of plastic optical fiber, and, more particularly, to the finishing of the end of a plastic optical fiber for insertion into an optical connector.
Optical plastic fibers are in general very easy to work with and are economical. An ongoing problem with the utilization of plastic optical fibers has been the problem of polishing the ends of a plastic optical fiber before insertion into an optical connector. The prior art polishing techniques have yielded connectors with a high insertion loss. These losses are typically in the 1.5 dB to 2.0 dB range. These insertion losses are high. For example, losses for multimode connectors made with silica fibers are less than 0.5 dB. Within the prior art, the finishing of ends of plastic optical fibers in the field and the manufacturing environment have utilized two or three different grits of optical polishing paper to polish the end of the optical. fiber. The utilization of optical polishing paper has resulted in the high insertion losses previously mentioned. Within the laboratory environment, it has been shown that by dipping the ends of optical fibers into an appropriate solvent that an instant good finish is achieved on the end of the optical fiber. The end finish achieved by the method of dipping the fiber into a solvent allows connector losses of typically 1 dB or lower. However, dipping optical fibers into a beaker full of solvent is not appropriate for field or factory utilization when fabricating optical connectors.
A departure in the art is achieved by an apparatus and method for finishing the end of a plastic optical fiber by a device having a semi-rigid or rigid base, a solvent liner for absorbing and holding a solvent, and a re-attachable pull-off cover for keeping the solvent from evaporating when not in use. To polish the end of a plastic optical fiber, the cover is peeled off, the end of the optical fiber is contacted with the solvent liner such that solvent is transferred to the end of the optical fiber, the cover may be reapplied (using a pressure sensitive adhesive integral to either the bottom of the peel off cover or the top of the liner), the excessive solvent, if any, is removed by using an appropriate swab, and the end of the plastic optical fiber is allowed to return to its normal state. The method works by the solvent temporarily dissolving the surface layer of the end of the optical fiber. The resulting surface tension automatically polishes the end of the optical fiber giving a better finish than that which could be achieved using optical polishing paper.
Other and further aspects of the present invention will become apparent during the course of the following description and by reference to the accompanying drawing.